She majors in relativistive psychology and sometimes has difficulty telling the difference between dream and reality (at least, in regards to Gensokyo). She believes subjectivity to be more true than objectivity. Her clan has had the ability to see boundaries since "ancient times" and seeks to dive into another world, despite such a thing being forbidden.

Together with her friend, Renko Usami, she has an interest in what would be considered the paranormal. Their club, consisting of only the two of them, describes itself as a club for necromancers. However, they don't do many of the things necromancers would normally be associated with. Instead, they investigate the possibility of other worlds and such. Specifically, they're interested in Gensokyo, the Netherworld, and the Moon, and seem to be among the few, or even the only humans from the outside world who know of Gensokyo's existence.

Although she's a human from the outside world, she possesses the ability to see boundaries. Per Maribel's words, she simply just does. This includes the ability to see other worlds, such as seeing the far side of the Moon. She also often visits Gensokyo in her dreams, and is sometimes chased by youkai. She can even bring back physical items.[1] Regarding this, considering that visiting another world is an entirely different matter compared to seeing it, Renko made the consideration that perhaps her ability has advanced to become "the ability to manipulate boundaries".

By the time of Trojan Green Asteroid, she isn't only able to travel across boundaries to other worlds freely, but is also capable of taking Renko with her. However, in order to reach TORIFUNE she needed to connect the gate of a shrine to Ame-no-Torifune with that of the one within the station. Renko notes later in Neo-traditionalism of Japan that her power seems to be connected to shrines. The duo's trip to TORIFUNE wasn't the first time the two have gone adventuring to other worlds.[2] It's noted by Maribel in Neo-traditionalism of Japan that while visiting TORIFUNE was a reality to Maribel, it was still a dream to Renko, which is why Maribel got injured by a chimera while Renko didn't. Renko privately realizes the same conclusion, recalling that the two encountered youkai during visits to other worlds that were real to Maribel but felt like figments of her imagination to Renko.

Renko notes that Maribel's power has grown rapidly stronger in Neo-traditionalism of Japan, set only a few days later. She can now see beyond to the other side of boundaries and show her visions to others by putting her hands over their eyes, although the transferred visions are unstable (but still adequate). She can now travel through worlds even while awake, and consciously taking back objects from those worlds is easy for her.

Maribel comes from a lineage which has had the ability to sense the supernatural since long ago[1]. Because of this, she has the ability to see borders. Society wasn't receptive to strange people, so she had to keep her ability a secret.[3]

She's hated lycoris (flowers which represent death) ever since she was a child because "they're creepy".

As opposed to how it has been revealed that Renko Usami's hometown is Tokyo, Maribel's hometown and home country is unclear. Since she fluently speaks Japanese with Renko, she probably has lived in Japan for a long time. However, she stated in Neo-Traditionalism of Japan that she doesn't have any relatives there.

Some aspects of Maribel appear to be based on Lafcadio Hearn, one of the first writers to spread knowledge of Japanese folklore to the West, who eventually married a Japanese woman and changed his name to Koizumi Yakumo. Lafcadio wrote several stories and baiku on the Japanese and Zen beliefs of butterflies and dreaming as one, which is a recurring theme for Maribel. This includes a well-known translation of the story The Dream of Akinosuke, where a man travelled to another world in his dreams only to find out in the end that it was real, although it turns out to be a world of ants instead of humans.

To add to this, several of Lafcadio's most well known works appear to correspond to Maribel's first four stories:

"In Ghostly Japan" was a collection of ghost stories by Lafcadio. ZUN stated he was trying to get a ghostly mood for Ghostly Field Club.

"Exotics and Retrospectives" was a collection of Lafcadio's musings about Japan. It contains a large article about Mount Fuji as well as a discussion about Zen, musings on paintings, and about the psychology of the color blue, among various other themes such as "beauty in memory" and "literature of the dead", which are all topics and themes that show up in Retrospective 53 minutes.

"The Romance of the Milky Way" may possibly be what Magical Astronomy was themed after. One of the short stories in it is called "The Mirror Maiden", and Magical Astronomy ends with Maribel about to manipulate a boundary using a reflection (in essence, Maribel is a mirror maiden). It was also Lafcadio's final work (published posthumously after his death), just as Magical Astronomy was Maribel's last story (at least for an extremely long time, until Trojan Green Asteroid was released almost six years later).

There's never been an official romanization for her name マエリベリー・ハーン (Maeriberii Haan), as well as the English spelling of her name is unclear, and "Maribel Hearn" is not an official spelling. Even ZUN does not seem to know about her name's English spelling nor origin[4]. Other than "Maribel" that's Spanish origin (a Hebrew name that's a very rough approximation of the katakana), there are also "Merryberry" and "Mæriberry" and the English "Maribelle". The Japanese toho-motoneta wiki posits that her first name could be a corruption of "mulberry", a berry that becomes purple (紫, the character for Yukari's name) upon ripening. In Hikawachou, a place with a deep connection to Yukari Yakumo, there is a factory called "Mulberry".

As for her last name, "Hearn" proved to be a popular alternative to "Han" (rough approximation of the katakana), since "Hearn" is actually transcribed as ハーン (haan) in Japanese. Also, ZUN was asked in a high school open lecture about the relation between Maribel and Yukari, ZUN said that there was this Lafcadio Hearn in the past. Furthermore, if you read Yukari's last name using the on reading, then "Yakumo" 八雲 becomes "Haun".

She is called "Merry" as a pet name by Renko Usami (sometimes rendered as "Mary"). It seems that Renko is not able to pronounce "Maeriberī" well. Judging by her name, Maribel may not actually be of Japanese ethnicity.

Maribel is talking with Renko about how she is visiting a strange world in her dreams. It starts out nicely but begins to become nightmarish as Maribel is attacked by youkai. Maribel has trouble figuring out what is reality and what is just a dream, and to further complicate the issue, she presents Renko with some of the items she had obtained in her dreams. Renko realizes the truth, and in the end must decide on which will be Maribel's reality.

In Retrospective 53 minutes, Maribel and Renko were on a train to Tokyo. They were looking at a simulated kaleido screen of the outside and discussing the trip, the view, and the nature of objectivity and subjectivity related to it. Renko commented on her, saying "You might be as carefree as the Tōhoku people though." The trip lasts 53 minutes.

The university campus is abuzz with news of public tours to the moon. Maribel and Renko talk about the world on the moon hidden from humans and eagerly try to plan their own trip to there. Maribel gets a special idea.

Maribel and Renko discuss the lost micro-habitat space station TORIFUNE, Maribel claiming that she has seen inside it and everything is still alive. Since the station contains a shrine to Ame-no-Torifune, they travel to another such shrine and use Maribel's ability to transport themselves there through their dreams. They discover that the interior has become a dense jungle, and are attacked by a chimera. Maribel wakes up with a cut on her arm and is sent to hospital.

While in hospital, Maribel is diagnosed with sleepwalking and hallucinations; believing this to be a previously unknown virus, the doctors send her to the mountains for isolation treatment. By the time she's released her powers have grown stronger and she now sees visions while awake. Maribel discusses Hell with Renko, but doesn't tell her that she physically travelled to Hell while in isolation. Renko tells Maribel that while she was in isolation, the news has been talking about discoveries of stone tools more than 25 million years old, though they were dismissed as a hoax. Maribel believes otherwise, and presents one she found herself. Maribel shows Renko a vision of the underground realm where she found it, and Renko recognises the Ame-no-Sakahoko as being there. Maribel calms down, no longer believing the place she saw to be Hell but the world of the gods. The two decide to find more such "Izanagi Objects" that lie unrecognised across Japan.

At Maribel's suggestion, the duo is planning on self-publishing a book, in which they would relate the stories of the mysterious worlds they had seen. Under the pen name of "Dr. Latency", Maribel is dictating to Renko her parts of the book, including a summary of the strange places she saw as well as her theories in her attempt to rationalize what was defying the common sense of the world.

Renko invites Maribel to the "Old Adam" bar, a special place where old-style alcohol is being served and said to be a gathering spot for those who can see illusions. Almost everyone there seems to have read the Swallowstone Naturalis Historia, the self-published fanzine Maribel and Renko made before, and believe its content entirely. The duo came here to hear the stories of the locals, hoping to find valuable information or even people that may have special abilities like them.

Possibly Relevant Facts to the Relationship Between Maribel & Yukari[edit]

ZUN's answer to the above question acknowledges a relationship between Maribel and Yukari Yakumo, but he only explicitly mentioned Lafcadio Hearn. The following facts and occurrences from various official sources may or may not be relevant to discerning the nature of this relationship, if it's possible to do so.

Maribel and Yukari's appearances are very similar to each other. Both have the same hair color and (in most official portrayals) eye color. In addition to this, both are always depicted wearing some combination of purple and red (the opposite colors of the visible spectrum), as well as ribbons tied in the shape of an eight, which is stated to be one of the meanings of Yukari's name. Both also wear a bonnet.

Both Maribel and Yukari have the ability to see boundaries. Unlike Yukari, however, Maribel is only stated to be able to see boundaries, not manipulate them. However, after Maribel told Renko about her dreams involving going to another world in Changeability of Strange Dream, Renko speculates that Maribel's ability is evolving into the ability to manipulate boundaries, even though such a thing should be impossible. In later stories such as Trojan Green Asteroid and Neo-traditionalism of Japan, Maribel is outright taking Renko with her to different worlds and bringing things back from them, showing that her ability has advanced far beyond merely being able to see boundaries. Her power has grown so much that "Renko couldn't help but think that Maribel was on the same level as those youkai."

One of Yukari's most famous uses of her ability was to go to the moon through its reflection on the lake. At the end of Magical Astronomy, Maribel also gets an idea of how to get to the moon while looking at its reflection in the lake, although the story ends there without explicitly saying what it was.

In Perfect Memento in Strict Sense, it mentions a couple speculations by various denizens of Gensokyo. One is that Yukari is a youkai from the outside world and spends her days and winters there (the time she claims to be sleeping). Another is that the outside world is Yukari's dream. It's also stated that Yukari's ability to manipulate boundaries includes the ability to enter dreams. Perfect Memento in Strict Sense doesn't state how valid these speculations are.

Maribel herself has visited Gensokyo in her dreams. In these dreams, she appears to still be Maribel and still be a human, as she says she is constantly attacked by youkai and runs from them in fear (which is the point when she typically wakes up).

Maribel is descended from a lineage which has had the ability to sense the supernatural since long ago. She herself exists in a time in the near future (when her stories are stated to take place). Yukari meanwhile has existed for at least over 1,200 years before and up to the present day (when the Touhou Project takes place).

Going by this, Maribel was apparently herself in Gensokyo during at least two different times hundreds of years apart. In Changeability of Strange Dream, Maribel visits a scarlet mansion with a maid (presumably the Scarlet Devil Mansion) at one point, and at another point gets lost in a bamboo forest (of which the events where she gets lost indicates it's the Bamboo Forest of the Lost). The memo in Perfect Memento in Strict Sense shows that the period in which she got lost was several hundreds of years before the present day, while the Scarlet Devil Mansion is known to have arrived in Gensokyo only recently.

Magical Astronomy ends with Maribel figuring out how to visit the moon. By Trojan Green Asteroid, it's stated she has actually gone to several fantastical new worlds by then.

In Cage in Lunatic Runagate, Yukari tells Ran a story where a youkai had once visited the moon just to look around and play as an indirect way of explaining how Yukari already knew about the trap set for her. Yukari refused to say that youkai's name, but Ran notes that youkai must have been Yukari herself.

The trap itself was made by creating a small discrepancy in time for the moon to become full each month which builds up over a long period of time. In Silent Sinner in Blue, Toyohime, while mocking Yukari, states that the trap takes a thousand years to be armed.

Yukari Yakumo is "probably" (quoted from Rinnosuke Morichika) not Yukari's original name. In Curiosities of Lotus Asia chapter 26, while analyzing the meaning of Yukari's name, Rinnosuke notes that Yukari is "probably" the name she chose for herself. Yukari's article in Perfect Memento in Strict Sense supports this by mentioning records from 1,200 years ago of a youkai that seems to be Yukari Yakumo (the wording shows those records didn't have the youkai's name recorded as Yukari Yakumo). As noted above, Maribel's namesake Lafcadio Hearn changed his name to Koizumi Yakumo when he became a Japanese citizen.

In Changeability of Strange Dream, Maribel also worries (to an unknown degree of seriousness) that her real name was forgotten because Renko always calls her "Merry".

Maribel believes that the world in her dreams (Gensokyo) is merely a dream, although it's so realistic that it leads her to panic about whether her dream is the true reality or not. Renko, however, believes that it's not a dream and that Maribel has actually visited another world. In the end, after debating on a choice which would lead Maribel to either stay in that world by convincing her it's real, or the "real" world by convincing her it's just a dream, Renko decides to tell Maribel to make her dream a reality.

Changeability of Strange Dream's Japanese title translates to "Changing Dreams in the Age of Science" while the synopsis includes the statement, "Two young female mediums, changing future nightmares into sweet dreams." Within the storyline where Maribel is trapped in Gensokyo, she comments, "The dreams usually end when I'm being chased by a youkai. It certainly seems like a nightmare, no matter how you see it, although..." followed by "Though, if I could change that nightmare to a pleasant dream, different from present reality..."

Yukari doesn't say how she feels about the state of Gensokyo as it is. Certainly, there are many events through out Gensokyo's history leading up to its current state which might have involved or been caused by her, but most can't be absolutely 100% confirmed. Akyuu Hieda, however, does comment in the afterword of Perfect Memento in Strict Sense, "These peaceful, yet stimulating times are surely a golden age for humans and youkai alike. There's no doubt that Gensokyo has become the way it is thanks to the isolation brought about by the Great Hakurei Barrier." which was "the solution endorsed by the youkai sages" (which is confirmed to include Yukari in Subterranean Animism). Yukari's own section also states she was a major supporter of the great barrier.

Renko Usami is the only other member of Maribel's Secret Sealing Club and a fellow student at Maribel's university. The two are very good friends, working together to seek out other worlds, travelling by train together to Renko's hometown, discussing going to the moon together, and Maribel confiding to Renko about her travels to another world in her dreams.

In one of her dreams, Maribel met a maid at a mansion that was a deep scarlet. The details of the meeting are unknown, but it must have been a friendly one given that Maribel was allowed to take some cookies home with her. It's unknown if the maid was indeed Sakuya.

In another one of her dreams, Maribel is rescued from a mouse or rabbityoukai by a mysterious girl surrounded by flames in the shape of a phoenix. Afraid of the girl, Maribel ran away. Although the mysterious girl is probably Mokou, it has never been explicitly confirmed.

Maribel encountered Yuyuko while investigating a supernatural hot spot (actually a place where ghosts come to the outside world to play). Merry didn't display any indication that she could see Yuyuko, though she appeared to feel a chill from her presence.

One of Maribel's known theme songs is titled "Merry, the Magician" (the other is "Strange Bird of the Moon, Illusion of Mysterious Cat" that she shares with Renko Usami), but ZUN said in Bohemian Archive in Japanese Red's music column that her theme song is "not necessarily because Merry is a magician" and she doesn't consciously perform any magical acts in any of her stories.

However, the end of Magical Astronomy refers to Maribel as "Merry, the Magician" just as she obtains the inspiration to perform an otherworldly act. She's also similar to a magician in the professional researcher sense, because she's researching other worlds and dreams, despite her world being one where all forms of energy are supposedly unified and science has reached its peak (according to Renko). In essence, magic is the only thing left to discover. Magic and science share many parallels, and Maribel is a person researching into this phenomenom in a world where science can't be researched further. Thus "Merry, the Magician" is a fitting moniker for her.

The actual name of Renko and Merry's club is "The Secret Sealing Club", not "Ghostly Field Club", as stated in Ghostly Field Club (which is a story about their club investigating a ghostly field).